1. Field of the Invention
The present invention relates to a wind turbine generator and a controlling method for controlling the wind turbine generator, and especially to a wind turbine generator and a method for controlling the wind turbine generator in which a nacelle is swiveled according to measurement results from an anemoscope and an anemometer.
2. Description of the Related Art
In recent years, from a view point of preserving the global environment, the use of wind turbine generators to generate reusable energy has become popular.
In general, a wind turbine generator comprises a rotor head equipped with blades, a nacelle accommodating a drive train and a rotation axis, and a tower supporting the nacelle. To improve power generation efficiency, most wind turbine generators adopt yaw rotation rotating the nacelle in the wind direction and a pitch control rotating the blades in a pitch direction.
As this type of a wind turbine generator, there is a wind turbine generator in which an azimuth of the nacelle is controlled based on measurement results from the anemometer and anemoscope provided on the nacelle. For instance, Patent Document 1 discloses to generate electric power efficiently by controlling the nacelle to follow the wind direction measured by the anemoscope when a fluctuation range of the wind direction measured by the anemoscope is smaller than a first parameter and a fluctuation range of the wind speed measured by the anemometer is smaller than a second parameter.
In this type of a wind turbine generator, the anemoscope is usually located in the downstream side of the wind turbine and thus the wind direction after blowing against the turbine blade is measured, which create measurement deviation. Therefore, a distribution curve of the fluctuation range of the power output (fluctuation range of the wind direction) relative to the wind direction measured by the anemoscope and the azimuth of the nacelle is obtained in advance and the measurement result of the anemoscope is corrected by using the fluctuation range of the peak in the distribution curve as a correction amount (e.g. Patent Document 2).
[Related Patent Documents]
    [Patent Document 1] JP2008-3090997A    [Patent Document 2] JP9-317760A (published in 1997)